Recently, there has been considerable interest in providing short-range wireless devices that are easily interoperable with other devices not necessarily produced by the same manufacturer. For instance, it is desirable to provide wireless headsets for mobile phones that will work with phones made by different manufacturers, or to provide keyboards, mice or other peripheral devices that will work with computers made by different manufacturers. Interoperability increases consumer choice and flexibility.
Various standards bodies and industry groups have defined standards for short-range wireless communication. One common example is the standard developed by the Bluetooth Special Interest Group (a non-profit organization) and licensed under the trademark Bluetooth®. The Bluetooth standard (referred to herein simply as “Bluetooth”) allows a host device such as a mobile phone and an accessory such as a headset to establish a wireless “pairing.” A pairing is usually established through a partly-automated, partly-manual process. For example, a wireless headset might send a signal identifying itself as a Bluetooth-enabled device. A mobile phone detects this signal and thus determine that the accessory is available for pairing. The mobile phone then prompts the user to enter a “passcode” or “PIN code” for the accessory. In some cases, the accessory's passcode is hard-coded in the accessory, and the user must look up the passcode (e.g., in documentation associated with the accessory) and enter it into the mobile phone. In other cases, the accessory's passcode is not hard-coded, and the accessory can make up an arbitrary passcode, which the user then enters into the mobile phone.
In either case, after receiving the passcode from the user, the mobile phone sends the passcode to the accessory. If the passcode matches the accessory's passcode, the accessory confirms the match, and a pairing is established. If the passcode does not match, the pairing is not established, and the user may be advised of the failure and allowed to retry. The number of retries is normally limited to prevent unauthorized users from determining passcodes through trial and error.
The Bluetooth standard also provides for encryption of data transmitted between paired devices. Symmetric-key cryptography, in which the same “link key” is used for both encryption and decryption, is used. The initial link key is generated independently by both devices using the passcode and a random number that is generated by one of the paired devices and transmitted to the other as cleartext. Thereafter, the two devices can generate a new link key. However, because the random number and the passcode are transmitted wirelessly as cleartext, an interloper could gain access to that information and determine the initial link key, then monitor subsequent transmissions.
Thus, existing procedures for configuring Bluetooth or other wireless links can be cumbersome, and the links themselves might not be as secure as desired.
It would therefore be desirable to provide improved methods for communicating information, such as information related to configuring a Bluetooth or other wireless communication link, between two devices.